If they're people that you might see more frequently, you should obviously befriend them and turn that disgust into fake pleasantries and condescending politeness. Only you should be in on the joke, though, don't make it obvious. Once you're "friends," you can come up with any number of excuses to avoid each other at future events.

I really find that turning my dislike of someone into actively mocking them by being nice works really well in the long-run. Everyone sees you as more mature and likeable and you get more power over the people you hate. The only problem is that, if they catch on, it can really destroy all of your relationships because nobody is sure whether you genuinely like them or not. That's why you should really use this tactic sparingly, and only when you absolutely have to interact with them. I think using it too often will probably make you feel bad, too, so that's another reason to keep the encounters brief.